Typically, a surface of a building such as a floor or a ceiling provides a fire barrier. A fire barrier resists the spread of a fire through it by providing a resistance to flammability, a resistance to heat transmission, and sufficient structural integrity to resist decomposing when exposed to heat or flames. The effectiveness of a fire barrier is often rated by exposure to a fire of specified and increasing intensity and a rating is a period of time, typically in hours during which the fire barrier is effective. When an aperture is made in one of these fire barriers, the effectiveness of the fire barrier is decreased dramatically. Often it is nonetheless desirable to create an aperture in a fire barrier, for example, to install recessed lighting or a floor drain. To restore the fire barrier and maintain an effective minimum resistance to fire, a construction worker will typically build a box of gypsum board and install it around the recessed fixture proximate the aperture created in the fire barrier. The construction of this box is a time-consuming task and provides no mechanism to ascertain to what degree the effectiveness of the fire barrier is restored. Moreover, many fixtures have large conduits such as pipes or cable servicing them. Constructing a box that provides egress for these conduits while maintaining integrity as a fire barrier is often a time-consuming and chancy process. It is also frequently difficult to install a fixture such as a box light into a fire box that is only slightly larger.